We are investigating the effects of cannabinoids, delta 9-tetrahydrocannabinal, cannabidiol and crude marihuana extract on (1) the male sex hormone and (2) corticosteroid hormone systems in the male rat. In (1), acute, subchronic and chronic studies are being carried out on the hypothalamo-pituitary-male gonadal system in intact, hypophysectomized and/or castrate animals. Serum gonadotropin and androgen levels will help to indicate sites of stimulatory or inhibitory effects or effects on steroid transpart and/or feedback regulation. Any secondary sex organ weight changes should also assist in these determinations. Effects of redced food consumption due to cannabinoid intubation on male reprodctive systems are being studied by pair feeding experiments. In (2), we shall investigate cannabinoid effects on the hypothalamo-pituitary-adrenal system in intact, hypophysectomized or adrenalectomized animals. Serum corticosterone and ACTH levels coupled with adrenal weight changes will assist in determining site(s) of stimulatory, inhibitory or feedback effects. Direct effects on thymus or liver will be investigated by measuring glucocorticoid cytoplasmic receptor activity as well as by possible tissue weight changes. Thus, in these studies, we are seeking the site(s) and mode(s) of action of cannabinoids on the androgenic and corticosteroid hormone systems.